1. Field
Exemplary embodiments relate to a light source module and a backlight unit.
2. Description of the Related Art
A light-emitting diode (LED) is a type of a semiconductor light emitting device that produces various colors of light through the recombination of electrons and holes at an interface between p and n type semiconductors when current is applied thereto. An LED has advantages in various properties such as a long lifespan, low power consumption, excellent initial driving characteristics, a high vibration resistance, and the like, as compared to filament-based light emitting devices, and thus demand therefore is continuously increasing. In particular, a group III nitride semiconductor able to emit blue light of a single wavelength region has been prominent.
Although a cold cathode fluorescent lamp (CCFL) has been used as a light source module in an LCD backlight unit in the related art, a CCFL containing mercury vapor may cause environmental pollution, may have a slow response speed, low color reproduction, and may not be appropriate for use with a small, thin and light LCD panel. Compared to a CCFL, an LED is environmentally-friendly, has a high speed response rate measured on the level of several nanoseconds, is effective in displaying streaming video signals, is impulsively driven, has color reproducibility of over 100%, and can optionally change a level of brightness, a color temperature, or the like of emitted light by adjusting an amount of light emitted by red, green, and blue LEDs, as well as having strengths suitable for the light, thin, and small LCD panels, and thus, LEDs have recently been employed in backlight light source modules in a positive manner.
The light source module used in the backlight unit, or the like may include a plurality of light emitting devices. The plurality of light emitting devices may have different characteristics such as varying levels of brightness, different required driving voltages, disparate color coordinates and the like during a manufacturing process. That is, manufactured light emitting devices are grouped into ranks according to the above characteristics. In this case, when a module is implemented by using light emitting devices having the same rank, since final product quality may be variable, a method of implementing the module uses light emitting devices having different ranks. As such, when light emitting devices having different ranks are applied to a single module, light emitting characteristics thereof may not be uniform across an overall light emission surface.